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1.
Braz J Biol ; 84: e284320, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39166691

RESUMEN

Piercing sucking pests attacking sweet pepper plants cause significant losses to its yield. Considering the undesirable effects of synthetic pesticides, field studies were conducted to evaluate the impact of new pesticides against piercing sucking insect pests of sweet pepper, as well as, their effects on some predators and pepper yield along two seasons of 2021-2022. The obtained results indicated that all tested pesticides effectively suppressed the sucking insect populations (aphids, white fly, thrips) 1,7,14 and 21 days after treatment along two sprays during two seasons. Imidacloprid proved to be the superior one over all other treatments where it recorded mean reduction% (98.91 and 97.27%) & (94.8 and 95.19%), (86.23 and 76.64%) & (80.92 and 88.55%) and (77.68 and 78.44%) & (90.70 and 68.57%) in white fly, aphids and thrips, respectively at 1st and 2nd sprays at 2021 and 2022 seasons, respectively. As for side effects of tested insecticides on natural enemies, Dimethoate induced the highest decrease (60.85 and 69.33%) & (54.02 and 63.41%), (65.52 and 64.74%) & (59.23 and 58.38%) and (64.24 and 59.48%) & (61.66 and 60.8%) on Chrysoperla carnea, Paederus alfierii and Coccinella spp at 1st and 2nd sprays at 2021 and 2022 seasons, respectively. On contrary, Spintoram induced the lowest effects on Chrysoperla carnea, Paederus alfierii and Coccinella spp, recording decrease percent (25.41 and 19.84%) & (15.02 and 12.50%), (11.94 and 11.24%) (16.99 and 18.02%) and (18.73 and15.07%) & (18.35 and18.38%) at1st and 2nd sprays at 2021 and 2022 seasons, respectively. With respect to the effect of tested insecticides on pepper yield, all tested insecticides increased the yield of green pepper fruits compared with control. Imidacloprid achieved the highest fruit yields along two seasons 6.43 and 6.52 (ton / fed.4200 m2) with increase percent 34.53 and 36.04% in yield over control at 2021 and 2022 seasons, respectively.


Asunto(s)
Áfidos , Capsicum , Insecticidas , Neonicotinoides , Nitrocompuestos , Estaciones del Año , Animales , Insecticidas/farmacología , Capsicum/efectos de los fármacos , Capsicum/parasitología , Nitrocompuestos/farmacología , Áfidos/efectos de los fármacos , Áfidos/fisiología , Neonicotinoides/farmacología , Imidazoles/farmacología , Thysanoptera/efectos de los fármacos , Thysanoptera/fisiología , Insectos/efectos de los fármacos , Insectos/fisiología , Factores de Tiempo
2.
Braz J Biol ; 84: e282436, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39194021

RESUMEN

The present study has been conducted to evaluate the effect of two sprays of seven pesticides at recommended dose on citrus brown mite, Eutetranychus orientalis and the side effects on their predatory mites, Euseius scutalis, Amblyseius swirskii, Phytoseiulus persimilis (Acari: Phytoseiidae) under field conditions at 2022 & 2023 seasons. The obtained results show that, all tested pesticides achieved high reduction % of E. orientalis ranged between (82.1-90.0%) and (81.6-87.1%) after the 1st and 2nd sprays of 2022 season, where it ranged between (84.9- 88.7%) and ( 79.7- 88.7%) after 1st and 2nd sprays of 2023 season. Abamectin recorded the highest reduction % against the citrus brown mite, whereas Congest pesticide recorded the lowest reduction % after the two sprays along 2022 & 2023 seasons. As for the side effects of tested pesticides on associated predatory mites, all pesticides were safely for E. scutalis numbers recording decrease % between (18.4-28.6%) and (16.2 -26.1%) after the 1st and 2nd spray at 2022 season , where it ranged between (15.3- 29.1%) and (19.6-32.0%) after the 1st and 2nd sprays of 2023 season. On contrary, imidacloprid was unsafely for E. scutalis numbers recording the highest mean decrease % after 1st and 2nd sprays during the two seasons. Also, all tested pesticides were safely for A. swirskii numbers, after the 1st and 2nd sprays of the two seasons recording decrease (from 10.9 to 28.1%) & (24.4 to 31.4%) for the 2022 season, and (19-38.9%) & (18.7-39.4%) at 2023 season. On contrary, imidacloprid was unsafely for A. swirskii numbers recorded the highest decrease % after 1st and 2nd sprays during the two seasons. As for, Ph. Persimilis numbers, all tested pesticides were safely, where it recorded low decrease % ranged between (17-33.8%) & (20.4-34.8%) after the 1st and 2nd sprays of 2022 season, and (24.3-39%) & (20.2-28.9%) after the 1st and 2nd sprays of 2023 season. On the other side, imidacloprid was unsafely for Ph. persimilis numbers recording the highest decrease % after the 1st and 2nd sprays during the two seasons. The present study proved that all tested pesticides were high effective against E. orientalis and appeared to be safely and selective for associated predatory mites except imidacloprid which was very harmful for all tested predatory mites, and it could be concluded that the tested pesticides, Fenpyroximate, Hexythiazox , Congest , Spirodiclofen, Abamectin, and Chlorfenapyr could be used in the Integrated Pest Management (IPM) programs for E. orientalis at citrus orchards.


Asunto(s)
Citrus , Neonicotinoides , Conducta Predatoria , Estaciones del Año , Tetranychidae , Animales , Conducta Predatoria/efectos de los fármacos , Tetranychidae/efectos de los fármacos , Acaricidas , Ácaros/efectos de los fármacos , Ácaros/clasificación , Nitrocompuestos , Ivermectina/análogos & derivados , Piretrinas , Plaguicidas/farmacología
3.
Adv Mater ; : e2405214, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39194391

RESUMEN

Wafer-scale transfer processes of 2D materials significantly expand their application space in scalable microelectronic devices with excellent and tunable properties through van der Waals (vdW) stacking. Unlike many 2D materials, wafer-scale transfer of MXene films for vdW contact engineering has not yet been reported. With their rich surface chemistry and tunable properties, the transfer of MXenes can enable enormous possibilities in electronic devices using interface engineering. Taking advantage of the MXene hydrophilic surface, a straightforward, green, and fast process for the transfer of MXene films at the wafer scale (4-inch) is developed. Uniform vdW stacking of several types of large-area heterojunctions including MXene/MXene (Ti3C2Tx, Nb2CTx, and V2CTx), MXene/MoS2, and MXene/Au is further demonstrated. Multilayer support is applied to minimize damage or deformation in the transfer process of patterned Ti3C2Tx film. It allows us to fabricate thin film transistors and manipulate the MXene/MoS2 interface through the intercalation of various 2D liquids. Particularly noteworthy is the significant enhancement of the interfacial carrier transfer efficiency by ≈2 orders of magnitude using hydrogen iodide (HI) intercalation. This finding indicates a wide range of possibilities for interface engineering by transferring MXene films and employing liquid-assisted interfacial intercalation.

4.
BMC Vet Res ; 20(1): 367, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39148099

RESUMEN

BACKGROUND: Recurrent dehydration causes chronic kidney disease in humans and animal models. The dromedary camel kidney has remarkable capacity to preserve water and solute during long-term dehydration. In this study, we investigated the effects of dehydration and subsequent rehydration in the camel's kidney histology/ultrastructure and changes in aquaporin/solute carrier proteins along with gene expression. RESULTS: In light microscopy, dehydration induced few degenerative and necrotic changes in cells of the cortical tubules with unapparent or little effect on medullary cells. The ultrastructural changes encountered in the cortex were infrequent during dehydration and included nuclear chromatin condensation, cytoplasmic vacuolization, mitochondrial swelling, endoplasmic reticulum/ lysosomal degeneration and sometimes cell death. Some mRNA gene expressions involved in cell stability were upregulated by dehydration. Lesions in endothelial capillaries, glomerular membranes and podocyte tertiary processes in dehydrated camels indicated disruption of glomerular filtration barrier which were mostly corrected by rehydration. The changes in proximal tubules brush borders after dehydration, were accompanied by down regulation of ATP1A1 mRNA involved in Na + /K + pump that were corrected by rehydration. The increased serum Na, osmolality and vasopressin were paralleled by modulation in expression level for corresponding SLC genes with net Na retention in cortex which were corrected by rehydration. Medullary collecting ducts and interstitial connective tissue were mostly unaffected during dehydration. CKD, a chronic nephropathy induced by recurrent dehydration in human and animal models and characterized by interstitial fibrosis and glomerular sclerosis, were not observed in the dehydrated/rehydrated camel kidneys. The initiating factors, endogenous fructose, AVP/AVPR2 and uric acid levels were not much affected. TGF-ß1 protein and TGF-ß1gene expression showed no changes by dehydration in cortex/medulla to mediate fibrosis. KCNN4 gene expression level was hardly detected in the dehydrated camel's kidney; to encode for Ca + + -gated KCa3.1 channel for Ca + + influx to instigate TGF-ß1. Modulation of AQP 1, 2, 3, 4, 9 and SLC protein and/or mRNAs expression levels during dehydration/rehydration was reported. CONCLUSIONS: Long-term dehydration induces reversible or irreversible ultrastructural changes in kidney cortex with minor effects in medulla. Modulation of AQP channels, SLC and their mRNAs expression levels during dehydration/rehydration have a role in water conservation. Cortex and medulla respond differently to dehydration/rehydration.


Asunto(s)
Acuaporinas , Camelus , Deshidratación , Riñón , Animales , Deshidratación/veterinaria , Acuaporinas/metabolismo , Acuaporinas/genética , Riñón/patología , Riñón/metabolismo , Masculino , Fluidoterapia/veterinaria , Regulación de la Expresión Génica , Proteínas Portadoras/metabolismo , Proteínas Portadoras/genética
5.
Adv Sci (Weinh) ; : e2404468, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39206684

RESUMEN

Single crystal perovskites have garnered significant attention as potential replacements for existing absorber layer materials. Despite the extensive investigations on their photoinduced charge-carriers dynamics, most of the time-resolved techniques focus on bulk properties, neglecting surface characteristic which plays a crucial role for their optoelectronic performance. Herein, 4D ultrafast scanning electron microscopy (4D-USEM) is utilized to probing the photogenerated carrier transport at the first few nanometers, alongside density functional theory (DFT) to track both defect centers and ions migration. Two compositions of mixed cation are investigated: FA0.6MA0.4PbI3 and FA0.4MA0.6PbI3, interestingly, the former displays a longer lifetime compared to the latter due the presence of a higher surface-defect centers. DFT calculations fully support that revealing samples with higher FA content have a lower energy barrier for iodide ions to migrate from the bulk to top layer, assisting in passivating surface vacancies, and a higher energy diffusion barrier to escape from surface to vacuum, resulting in fewer vacancies and longer-lived hole-electron pairs. These findings manifest the influence of cation selection on charge carrier transport and formation of defects, and emphasize the importance of understanding ion migrations role in controlling surface vacancies to assist engineering high-performance optoelectronic devices based on single crystal perovskites.

6.
ACS Nano ; 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38951541

RESUMEN

Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb3+), commonly referred to as Gadox, is a widely used scintillator material due to its exceptional X-ray attenuation efficiency and high light yield. However, Gadox-based scintillators suffer from low X-ray spatial resolution due to their large particle size, which causes significant light scattering. To address this limitation, we report the synthesis of terbium-doped colloidal Gadox nanoplatelets (NPLs) with near-unity photoluminescence quantum yield (PLQY) and high radioluminescence light yield (LY). In particular, our investigation reveals a strong correlation between PLQY, LY, particle size, and Tb3+concentration. Our synthetic approach allows precise control over the lateral size and thickness of the Gadox NPLs, resulting in a LY of 50,000 photons/MeV. Flexible scintillating screens fabricated with the solution-processable Gadox NPLs exhibited a 20 lp/mm X-ray spatial resolution, surpassing commercial Gadox scintillators. These high-performance and flexible Gadox NPL-based scintillators enable enhanced X-ray imaging capabilities in medicine and security. Our work provides a framework for designing nanomaterial scintillators with superior spatial resolution and efficiency through precise control of dimensions and dopant concentration.

7.
Adv Mater ; : e2404291, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38975670

RESUMEN

The transition toward hydrogen gas (H2) as an eco-friendly and renewable energy source necessitates advanced safety technologies, particularly robust sensors for H2 leak detection and concentration monitoring. Although palladium (Pd)-based materials are preferred for their strong H2 affinity, intense palladium-hydrogen (Pd-H) interactions lead to phase transitions to palladium hydride (PdHx), compromising sensors' durability and detection speeds after multiple uses. In response, this study introduces a high-performance H2 sensor designed from thiolate-protected Pd nanoclusters (Pd8SR16), which leverages the synergistic effect between the metal and protective ligands to form an intermediate palladium-hydrogen-sulfur (Pd-H-S) state during H2 adsorption. Striking a balance, it preserves Pd-H binding affinity while preventing excessive interaction, thus lowering the energy required for H2 desorption. The dynamic adsorption-dissociation-recombination-desorption process is efficiently and highly reversible with Pd8SR16, ensuring robust and rapid H2 sensing at parts per million (ppm). The Pd8SR16-based sensor demonstrates exceptional stability (50 cycles; 0.11% standard deviation in response), prompt response/recovery (t90 = 0.95 s/6 s), low limit of detection (LoD, 1 ppm), and ambient temperature operability, ranking it among the most sensitive Pd-based H2 sensors. Furthermore, a multifunctional prototype demonstrates the practicality of real-world gas sensing using ligand-protected metal nanoclusters.

9.
J Am Chem Soc ; 146(23): 16295-16305, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38816788

RESUMEN

Atomically precise metal nanoclusters (NCs) have become an important class of catalysts due to their catalytic activity, high surface area, and tailored active sites. However, the design and development of bond-forming reaction catalysts based on copper NCs are still in their early stages. Herein, we report the synthesis of an atomically precise copper nanocluster with a planar core and unique shell, [Cu45(TBBT)29(TPP)4(C4H11N)2H14]2+ (Cu45) (TBBT: 4-tert-butylbenzenethiol; TPP: triphenylphosphine), in high yield via a one-pot reduction method. The resulting structurally well-defined Cu45 is a highly efficient catalyst for the hydroboration reaction of alkynes and alkenes. Mechanistic studies show that a single-electron oxidation of the in situ-formed ate complex enables the hydroboration via the formation of boryl-centered radicals under mild conditions. This work demonstrates the promise of tailored copper nanoclusters as catalysts for C-B heteroatom bond-forming reactions. The catalysts are compatible with a wide range of alkynes and alkenes and functional groups for producing hydroborated products.

10.
Front Neurol ; 15: 1373890, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38694780

RESUMEN

Background: Headache disorder is the second-highest cause of disability worldwide; however, data are scarce on headache among adolescents, especially in Africa. There has yet to be published data on headache among adolescents in Sudan, the third-largest country in Africa. This study aimed to assess the prevalence of primary headache disorders and associated factors among adolescents (10-19 years) in eastern Sudan. Methods: A community-based cross-sectional study was conducted in the city of Gadarif in eastern Sudan. Questionnaires were used to gather the adolescents' sociodemographic characteristics. Headache diagnostic questions were based on the beta version of the International Classification of Headache Disorders-III (ICHD-3). Multivariate analysis was conducted to assess the associated factors for primary headache disorders, and the results were expressed as risk ratios (RRs) and 95.0% confidence interval (CI). Results: Of the 401 enrolled adolescents, 186 (46.4%) and 215 (53.6%) were male and female, respectively. The median (IQR) age was 14.0 (12.1-16.2) years. Eighty-one (20.2%) of the 401 adolescents reported experiencing primary headache disorders, including migraine with aura in 16 (4.0%), migraine without aura in 33 (8.2%), tension-type in 14 (3.5%), and undifferentiated headache in 18 (4.5%) adolescents. The prevalence of primary headache disorders was significantly higher in females than in males [55/215 (67.9%) vs. 26/186 (32.1%), p = 0.004]. In the multivariate analysis, increased age (RR = 1.09, 95.0 CI = 1.02-1.16) and being female (RR = 1.75, 95.0 CI = 1.14-2.67) were associated with increased RR of primary headache disorders. Parents' education level and occupation, smoking/snuff use, and body mass index were not associated with primary headache disorders. Conclusion: One-fifth of the adolescents in eastern Sudan reported experiencing primary headache disorders, which was more common in females and with increased age.

11.
Med J Malaysia ; 79(3): 337-341, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38817068

RESUMEN

INTRODUCTION: The aim of this study was to evaluate a group of infants born to women with tuberculosis (TB) during pregnancy to determine the neonatal morbidities and its outcomes associated with tuberculosis in pregnancy. MATERIALS AND METHODS: Data from January 2007 to December 2021 was collected for analysis as part of a retrospective cohort study. This study was conducted in a tertiary public hospital in Malaysia, Hospital Sultan Idris Shah (HSIS). Cases were identified from the hospital's bacille Calmette-Guerin (BCG) vaccination notification forms and merged with records from the neonatal intensive care unit's census. Controls were infants born to mothers unaffected by TB within the same hospital and year as the index case (1:4 ratio). Descriptive statistics and logistic regression were used to analyse the data. The main outcome measures were the risk of congenital tuberculosis, premature birth, low birth weight, small for gestational age and low APGAR score. RESULTS: Data from January 2007 to December 2021 was collected for analysis as part of a retrospective cohort study. This study was conducted in a tertiary public hospital in Malaysia, Hospital Sultan Idris Shah (HSIS). Cases were identified from the hospital's bacille Calmette-Guerin (BCG) vaccination notification forms and merged with records from the neonatal intensive care unit's census. Controls were infants born to mothers unaffected by TB within the same hospital and year as the index case (1:4 ratio). Descriptive statistics and logistic regression were used to analyse the data. The main outcome measures were the risk of congenital tuberculosis, premature birth, low birth weight, small for gestational age and low APGAR score.


Asunto(s)
Centros de Atención Terciaria , Tuberculosis , Humanos , Femenino , Estudios Retrospectivos , Embarazo , Recién Nacido , Malasia/epidemiología , Centros de Atención Terciaria/estadística & datos numéricos , Tuberculosis/epidemiología , Adulto , Complicaciones Infecciosas del Embarazo/epidemiología , Resultado del Embarazo , Nacimiento Prematuro/epidemiología , Recién Nacido de Bajo Peso , Masculino , Puntaje de Apgar , Estudios de Cohortes
12.
Artículo en Inglés | MEDLINE | ID: mdl-38573046

RESUMEN

Tracking the dynamics of ultrafast hole injection into copper thiocyanate (CuSCN) at the interface can be experimentally challenging. These challenges include restrictions in accessing the ultraviolet spectral range through transient electronic spectroscopy, where the absorption spectrum of CuSCN is located. Time-resolved vibrational spectroscopy solves this problem by tracking marker modes at specific frequencies and allowing direct access to dynamical information at the molecular level at donor-acceptor interfaces in real time. This study uses photoabsorber PM6 (poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)-benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))]) as a model system to explore and decipher the hole transfer dynamics of CuSCN using femtosecond (fs) mid-infrared (IR) spectroscopy. The time-resolved results indicate that excited PM6 exhibits a sharp vibrational mode at 1599 cm-1 attributed to the carbonyl group, matching the predicted frequency position obtained from time-dependent density functional theory (DFT) calculations. The fs mid-IR spectroscopy demonstrates a fast formation (<168 fs) and blue spectral shift of the CN stretching vibration from 2118 cm-1 for CuSCN alone to 2180 cm-1 for PM6/CuSCN, confirming the hole transfer from PM6 to CuSCN. The short interfacial distance and high frontier orbital delocalization obtained from the interfacial DFT models support a coherent and ultrafast regime for hole transfer. These results provide direct evidence for hole injection at the interface of CuSCN for the first time using femtosecond mid-IR spectroscopy and serve as a new investigative approach for interfacial chemistry and solar cell communities.

13.
Sci Rep ; 14(1): 5839, 2024 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-38462649

RESUMEN

Many scientific phenomena are linked to wave problems. This paper presents an effective and suitable technique for generating approximation solutions to multi-dimensional problems associated with wave propagation. We adopt a new iterative strategy to reduce the numerical work with minimum time efficiency compared to existing techniques such as the variational iteration method (VIM) and homotopy analysis method (HAM) have some limitations and constraints within the development of recurrence relation. To overcome this drawback, we present a Sawi integral transform ( S T) for constructing a suitable recurrence relation. This recurrence relation is solved to determine the coefficients of the homotopy perturbation strategy (HPS) that leads to the convergence series of the precise solution. This strategy derives the results in algebraic form that are independent of any discretization. To demonstrate the performance of this scheme, several mathematical frameworks and visual depictions are shown.

14.
J Phys Chem Lett ; 15(11): 2988-2994, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38457267

RESUMEN

Intermolecular charge transfer (CT) complexes have emerged as versatile platforms with customizable optical properties that play a pivotal role in achieving tunable photoresponsive materials. In this study, we introduce an innovative approach for enhancing the modulation bandwidth and net data rates in optical wireless communications (OWCs) by manipulating combinations of monomeric molecules within intermolecular CT complexes. Concurrently, we extensively investigate the intermolecular charge transfer mechanism through diverse steady-state and ultrafast time-resolved spectral techniques in the mid-infrared range complemented by theoretical calculations using density functional theory. These intermolecular CT complexes empower precise control over the -3 dB bandwidth and net data rates in OWC applications. The resulting color converters exhibit promising performance, achieving a net data rate of ∼100 Mb/s, outperforming conventional materials commonly used in the manufacture of OWC devices. This research underscores the substantial potential of engineering intermolecular charge transfer complexes as an ongoing progression and commercialization within the OWC. This carries profound implications for future initiatives in high-speed and secure data transmission, paving the way for promising endeavors in this area.

15.
J Am Chem Soc ; 146(11): 7373-7385, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38433410

RESUMEN

Organic-inorganic atomically precise nanoclusters provide indispensable building blocks for establishing structure-property links in hybrid condensed matter. However, robust glasses of ligand-protected nanocluster solids have yet to be demonstrated. Herein, we show [Cu4I4(PR3)4] cubane nanoclusters coordinated by phosphine ligands (PR3) form robust melt-quenched glasses in air with reversible crystal-liquid-glass transitions. Protective phosphine ligands critically influence the glass formation mechanism, modulating the glasses' physical properties. A hybrid glass utilizing ethyldiphenylphosphine-based nanoclusters, [Cu4I4(PPh2Et)4], exhibits superb optical properties, including >90% transmission in both visible and near-infrared wavelengths, negligible self-absorption, near-unity quantum yield, and high light yield. Experimental and theoretical analyses demonstrate the structural integrity of the [Cu4I4(PPh2Et)4] nanocluster, i.e., iodine-bridged tetranuclear cubane, has been fully preserved in the glass state. The strong internanocluster CH-π interactions found in the [Cu4I4(PPh2Et)4] glass and subsequently reduced structural vibration account for its enhanced luminescence properties. Moreover, this highly transparent glass enables performant X-ray imaging and low-loss waveguiding in fibers drawn above the glass transition. The discovery of "nanocluster glass" opens avenues for unraveling glass formation mechanisms and designing novel luminescent glasses of well-defined building blocks for advanced photonics.

16.
Nat Nanotechnol ; 19(8): 1091-1100, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38514820

RESUMEN

Quantum information processing-which relies on spin defects or single-photon emission-has shown quantum advantage in proof-of-principle experiments including microscopic imaging of electromagnetic fields, strain and temperature in applications ranging from battery research to neuroscience. However, critical gaps remain on the path to wider applications, including a need for improved functionalization, deterministic placement, size homogeneity and greater programmability of multifunctional properties. Colloidal semiconductor nanocrystals can close these gaps in numerous application areas, following years of rapid advances in synthesis and functionalization. In this Review, we specifically focus on three key topics: optical interfaces to long-lived spin states, deterministic placement and delivery for sensing beyond the standard quantum limit, and extensions to multifunctional colloidal quantum circuits.

17.
Mater Horiz ; 11(10): 2494-2505, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38477151

RESUMEN

Atomically precise copper nanoclusters (NCs) are an emerging class of nanomaterials for catalysis. Their versatile core-shell architecture opens the possibility of tailoring their catalytically active sites. Here, we introduce a core-shell copper nanocluster (CuNC), [Cu29(StBu)13Cl5(PPh3)4H10]tBuSO3 (StBu: tert-butylthiol; PPh3: triphenylphosphine), Cu29NC, with multiple accessible active sites on its shell. We show that this nanocluster is a versatile catalyst for C-heteroatom bond formation (C-O, C-N, and C-S) with several advantages over previous Cu systems. When supported, the cluster can also be reused as a heterogeneous catalyst without losing its efficiency, making it a hybrid homogeneous and heterogeneous catalyst. We elucidated the atomic-level mechanism of the catalysis using density functional theory (DFT) calculations based on the single crystal structure. We found that the cooperative action of multiple neighboring active sites is essential for the catalyst's efficiency. The calculations also revealed that oxidative addition is the rate-limiting step that is facilitated by the neighboring active sites of the Cu29NC, which highlights a unique advantage of nanoclusters over traditional copper catalysts. Our results demonstrate the potential of nanoclusters for enabling the rational atomically precise design and investigation of multi-site catalysts.

18.
Adv Mater ; 36(21): e2312053, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38340045

RESUMEN

The exacerbation of inherent light scattering with increasing scintillator thickness poses a major challenge for balancing the thickness-dependent spatial resolution and scintillation brightness in X-ray imaging scintillators. Herein, a thick pixelated needle-like array scintillator capable of micrometer resolution is fabricated via waveguide structure engineering. Specifically, this involves integrating a straightforward low-temperature melting process of manganese halide with an aluminum-clad capillary template. In this waveguide structure, the oriented scintillation photons propagate along the well-aligned scintillator and are confined within individual pixels by the aluminum reflective cladding, as substantiated from the comprehensive analysis including laser diffraction experiments. Consequently, thanks to isolated light-crosstalk channels and robust light output due to increased thickness, ultrahigh spatial resolutions of 60.8 and 51.7 lp mm-1 at a modulation transfer function (MTF) of 0.2 are achieved on 0.5 mm and even 1 mm thick scintillators, respectively, which both exceed the pore diameter of the capillary arrays' template (Φ = 10 µm). As far as it is known, these micrometer resolutions are among the highest reported metal halide scintillators and are never demonstrated on such thick scintillators. Here an avenue is presented to the demand for thick scintillators in high-resolution X-ray imaging across diverse scientific and practical fields.

19.
J Am Chem Soc ; 146(8): 5393-5401, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38359303

RESUMEN

Disentangling electronic and thermal effects in photoexcited perovskite materials is crucial for photovoltaic and optoelectronic applications but remains a challenge due to their intertwined nature in both the time and energy domains. In this study, we employed temperature-dependent variable-angle spectroscopic ellipsometry, density functional theory calculations, and broadband transient absorption spectroscopy spanning the visible to mid-to-deep-ultraviolet (UV) ranges on MAPbBr3 thin films. The use of deep-UV detection opens a new spectral window that enables the exploration of high-energy excitations at various symmetry points within the Brillouin zone, facilitating an understanding of the ultrafast responses of the UV bands and the underlying mechanisms governing them. Our investigation reveals that the photoinduced spectral features remarkably resemble those generated by pure lattice heating, and we disentangle the relative thermal and electronic contributions and their evolutions at different delay times using combinations of decay-associated spectra and temperature-induced differential absorption. The results demonstrate that the photoinduced transients possess a significant thermal origin and cannot be attributed solely to electronic effects. Following photoexcitation, as carriers (electrons and holes) transfer their energy to the lattice, the thermal contribution increases from ∼15% at 1 ps to ∼55% at 500 ps and subsequently decreases to ∼35-50% at 1 ns. These findings elucidate the intricate energy exchange between charge carriers and the lattice in photoexcited perovskite materials and provide insights into the limited utilization efficiency of photogenerated charge carriers.

20.
J Am Chem Soc ; 146(6): 4144-4152, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38315569

RESUMEN

Circularly polarized light-emitting diodes (CP-LEDs) are critical for next-generation optical technologies, ranging from holography to quantum information processing. Currently deployed chiral luminescent materials, with their intricate synthesis and processing and limited efficiency, are the main bottleneck for CP-LEDs. Chiral metal nanoclusters (MNCs) are potential CP-LED materials, given their ease of synthesis and processability as well as diverse structures and excited states. However, their films are usually plagued by inferior electronic quality and aggregation-caused photoluminescence quenching, necessitating their incorporation into host materials; without such a scheme, MNC-based LEDs exhibit external quantum efficiencies (EQEs) < 10%. Herein, we achieve an efficiency leap for both CP-LEDs and cluster-based LEDs by using novel chiral MNCs with aggregation-induced emission enhancement. CP-LEDs using enantiopure MNC films attain EQEs of up to 23.5%. Furthermore, by incorporating host materials, the devices yield record EQEs of up to 36.5% for both CP-LEDs and cluster-based LEDs, along with electroluminescence dissymmetry factors (|gEL|) of around 1.0 × 10-3. These findings open a new avenue for advancing chiral light sources for next-generation optoelectronics.

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